The increasing convergence of services of telecommunication providers with services of the Internet area induces eTel to start a research project evaluating the possibilities of a fusion of classical enterprise communication with mobile terminals. In the context of the project DERI’s task was, among other things, the development of a software solution based on Office-PBX Swyx, the development of the software architecture and specification of the APIs as well as the setup of a pilot environment (SIP capable terminal, Office PBX Swyx).